14 cities
| City | Rank | 2025 Pop. ↓ | 2020 Pop. | Annual Change | Density | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Humboldt | 1 | 4,771 | 4,784 | -0.06% | 1,026 | 5 | City |
| Dakota City | 2 | 765 | 759 | 0.13% | 1,048 | 1 | City |
| Gilmore City | 3 | 484 | 484 | 0% | 391 | 1 | City |
| Livermore | 4 | 382 | 381 | 0% | 587 | 1 | City |
| Bode | 5 | 303 | 305 | -0.33% | 750 | 0 | City |
| Renwick | 6 | 227 | 229 | -0.44% | 227 | 1 | City |
| Thor | 7 | 182 | 179 | 0% | 183 | 1 | City |
| Rutland | 8 | 115 | 118 | -0.86% | 128 | 1 | City |
| St. Joseph | 9 | 84 | 122 | 7.69% | 97 | 1 | CDP |
| Bradgate | 10 | 76 | 76 | 0% | 145 | 1 | City |
| Irvington | 11 | 68 | 41 | 7.94% | 67 | 1 | CDP |
| Hardy | 12 | 55 | 55 | 0% | 122 | 0 | City |
| Ottosen | 13 | 41 | 41 | 0% | 84 | 0 | City |
| Rodman | 14 | 27 | 29 | -3.57% | 185 | 0 | City |
Humboldt is the largest city in Humboldt County, with a population of 4,771.
Rodman is the smallest city in Humboldt County, with a population of 27.
There are 14 cities in Humboldt County, Iowa.